Composition and method for hydrophilic treatment of aluminum or aluminum alloy

Abstract

Here are provided a composition for hydrophilic treatment of aluminum or aluminum alloy which can form film having persistent corrosion resistance and hydrophilicity and not generating odor, and a method for hydrophilic treatment.Namely, provided by the invention are a composition for hydrophilic treatment of aluminum or an aluminum alloy which comprises(P1) a water-soluble polymer having as a constitution unit monomer(s) (I) represented by the formula wherein, R1 represents a hydrogen atom or a methyl group, and R2 and R3 are the same or different, and each represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a benzyl group or a hydroxyalkyl group having 2 or 3 carbon atoms, and obtained by homopolymerization or copolymerization of the monomer(s) (I),(A) a water-soluble trivalent chromium compound,(B) a water-soluble zirconium compound or titanium compound, and, if necessary, further water, and wherein the mutual rate of P1, A and B is such that, based on 100 weight parts of the solid matter of P1, A is 0.01 to 70 weight parts and B is 0.001 to 70 weight parts, and a method for hydrophilic treatment using it.

What is claimed is:  
     
       1. A composition comprising components (P1), (A), (B) and (C) for hydrophilic treatment of an aluminum or aluminum alloy wherein: 
       (P1) a water-soluble polymer obtained by a polymerization process selected from the group consisting of:  
       (i) homopolymerizing a monomer (I) represented by the formula:                    
        wherein R 1  represents a hydrogen atom or a methyl group and R 2  and R 3  are the same or different, and each represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a benzyl group or a hydroxyalkyl group having 2 or 3 carbon atoms,  
       (ii) copolymerizing two or more of monomers (I),  
       (iii) copolymerizing at least one monomer (I) with another monomer (II) copolymerizable with the monomer (I) or salt(s) of the monomer(s) (II) to provide a ratio of monomer (I) in the total monomers of 40% by mol or more, and  
       (iv) subjecting the homopolymer or copolymer resulting from polymerization (i), (ii) or (iii) to a modification process selected from the group consisting of  
       (1) converting amido groups to carboxyl groups by hydrolysis,  
       (2) converting amido groups to amino groups by a Hofmann rearrangement,  
       (3) converting amido groups to —CONH—CH 2 —N(R 4 )(R 5 ) by a Mannich reaction using HN(R 4 )(R 5 ) and formaldehyde  
       wherein R 4  and R 5  are the same or different, and each represents an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 2 or 3 carbon atoms or a benzyl group,  
       (4) introducing a —CONH—R 6 —NH 2  group by reacting side chain ester groups with alkylenediamine (H 2 N—R 6 —NH 2 ) wherein R 6  represents an alkylene group having 2 to 6 carbon atoms, and  
       (5) converting the amino or substituted amino groups resulting from reactions (2) to (4) to quaternary ammonium through alkylation,  
       (A) a water-soluble trivalent chromium compound;  
       (B) a water-soluble zirconium compound or titanium compound; and  
       (C) water;  
       provided that the ratio of (P1), (A) and (B) is such that, based on 100 weight parts of the solids of (P1), (A) is 0.01 to 70 weight parts and (B) is 0.001 to 70 weight parts and provided the composition is substantially completely free of a hexavalent chromium compound.  
     
     
       2. The composition according to claim  1  wherein monomer (I) is selected from the group consisting of acrylamide, methacrylamide, N-methlacrylamide and N,N-dimethylacrylamide. 
     
     
       3. The composition according to claim  1 , which further contains a second water-soluble polymer (P2) in an amount of 1 to 400 weight parts based on 100 weight parts of (P1) in solid weight basis, wherein (P2) a water-soluble polymer obtained by 
       homopolymerization of a monomer (III) or a salt thereof having in each molecule a carboxyl group, a sulfonic acid group, a phosphonic acid group, a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, a hydroxyl group, a glycidyl group or an amido group, provided that monomer (III) is different from monomer (I),  
       copolymerization of two or more of monomers (III) and salts thereof, or copolymerization of monomers (III) or salts thereof with a nonioic monomer copolymerizable with the monomer (III) or salts thereof provided it has neither a hydroxyl group, a glycidyl group nor an amido group,  
       wherein the ratio of monomer (III) or salts thereof to the total monomers in polymer (P2) is 40% by mol or more.  
     
     
       4. A composition according to claim  3  wherein the nonioic monomer copolymerizable with the monomer (III) or salts thereof is selected from the group consisting of styrene, alkyl (C=1 to 8) (meth)acrylate and vinyl acetate. 
     
     
       5. The composition according to claim  1  which further contains an antibacterial agent having a decomposition temperature of 100° C. or more. 
     
     
       6. The composition according to claim  3  which further contains an antibacterial agent having a decomposition temperature of 100° C. or more. 
     
     
       7. The composition according to claim  1 , wherein the water-soluble polymer is the one obtained by copolymerizing monomer (I) with monomer (II), and monomer (II) is selected from the group consisting of 2-hydroxyalkyl (C=2 or 3) (meth)acrylate, diacetoneacrylamide, N-methylolacrylamide, acryloylmorpholine, acrylonitrile, alkyl (C=1 to 6)(meth)acrylate, styrene, vinyl acetate, a monomer represented by the formula:                    
       wherin R 1  represents a hydrogen atom or a methyl group, and M 1  represents one of the following groups:                    
        wherein R a  and R b  are the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, a phenyl group or a benzyl group, and y represents an integer of 1 to 3,  
       a monomer represented by the formula                    
        wherein R 1  represents a hydrogen atom or a methyl group, and M 2  represents one of the following groups:                    
       maleic anhydride and itaconic acid. 
     
     
       8. The composition according to claim  3  wherein the monomer (III) is selected from the group consisting of a monomer represented by the formula:                    
       wherein R 1  represents a hydrogen atom or a methyl group, and M 2  represents one of the following groups:                    
       maleic anhydride and itaconic acid, 
       a monomer represented by the formula:                    
        wherein R 1  represents a hydrogen atom or a methyl group, and M 1  represents one of the following groups:                    
        wherein R a  and R b  are the same or different, and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, a phenyl group or a benzyl group, and y represents an integer of 1 to 3, and 2-hydroxyalkyl (C=2 or 3) (meth)acrylate, N-methylolacrylamide and diacetoneacrylamide.